Pius, P. C. C. P. (1932). Encyclical Letter of His Holiness, Pope Pius XI. Washington, D.C..
Dyfyniad Arddull ChicagoPius, Pope; Catholic Church. Pope. Encyclical Letter of His Holiness, Pope Pius XI. Washington, D.C., 1932.
Dyfyniad MLAPius, Pope; Catholic Church. Pope. Encyclical Letter of His Holiness, Pope Pius XI. Washington, D.C., 1932.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.